TW-8: Moves settings into the DB
TW-8: Do not load settings at load time

* it's a bad habit to have side effect at load time
* it breaks tests
TW-8: Remove `serializer` as it is now useless
TW-8: Adds an exception handler if mongo is not found
Merge remote-tracking branch 'origin/develop' into feature/TW-8_Move_settings_from_binary_file_to_the_DB

Conflicts:
	src/server/teamwall/handler.clj
Merge pull request #6 from teamwall/feature/TW-8_Move_settings_from_binary_file_to_the_DB

TW-8: Moves settings into the DB
Merge remote-tracking branch 'origin/develop' into feature/TW-14_Code_Review

Conflicts:
	src/server/teamwall/db.clj
	src/server/teamwall/serializer.clj